1. Field of the Invention
The present invention relates to chemical lasers; and more particularly, the invention relates to improvements in the operation of such lasers.
2. Description of the Prior Art
Conventional lasers can be divided, for example, into two groups or classes: pulsed lasers and continuous wave lasers. The line of division depends upon the mode and manner of developing in the lasing medium the requisite energy for the lasing action. Early lasers were usually pulsed lasers. By one mechanism or another, usually through application of an electric field or an equivalent source of energy, the lasing medium was "charged" or "pumped" to an "active" or "metastable" state for a certain period of time, followed by a lasing action amounting to an energy "discharge", also lasting for a certain period of time, and so forth, in periodic sequence.
A continuous wave laser, on the other hand, is usually based on a mechanism in which the extraction of optical energy from the active lasing medium as well as the pumping of that medium for transferring energy to the molecules thereof are continouous processes. This overlap and coincidence of pumping and extraction is not necessarily carried out concurrently on the same portions of the medium. Rather, pumping may be carried out in one space or chamber, and the pumped medium may then be transferred to the laser resonant cavity for energy extraction. Take, for example, a chemical laser; the medium here is prepared by continuous chemical reactions, at least some of which occur outside the resonant cavity. The medium flows from the chemical reaction chamber into the resonant cavity, and the metastable state for lasing is established continuously within the resonant cavity. The chemical reaction, the resonant cavity pumping process, and consequently the lasing process, do all occur continously, but at least in parts in different locations.
Recent developments in the field of laser engineering have shown that more powerful lasers will depend upon chemical reactions for obtaining the metastable state at a sufficiently high density and in sufficiently large volume. On the other hand, it was found that energy transfer by means of a laser beam is more efficient when carried out on a pulsating basis rather than by continouous waves.